1. Field of the Invention
The present invention relates to an image forming apparatus and a fluid injecting apparatus which can suitably inject a solvent for forming an image to an image recording material such as a photosensitive material, an image receiving material and the like.
2. Description of the Related Art
An image forming apparatus for performing an image recording operation by using two kinds of image recording materials, for example, a photosensitive material and an image receiving material is known.
A solvent application portion for forming an image having a tank storing a solvent for forming an image which is used for application to the photosensitive material is disposed within this kind of image forming apparatus, and further a heat developing and transferring portion comprising a heating drum and an endless pressing belt pressed into contact with the outside of the heating drum and rotating with the heating drum is disposed within the image forming apparatus.
A photosensitive material on which the image is exposed while being held and conveyed within the image forming apparatus is soaked in the tank in which water acting as the image forming solvent is stored at the image forming solvent application portion, and is fed to the heat developing and transferring portion after the water is applied thereon. On the other hand, the image receiving material is fed to the heat developing and transferring portion in the same manner as the photosensitive material.
In the heat developing and transferring portion, the photosensitive material after the water is applied thereon is put over the image receiving material and in this state wound around the outer periphery of the heating drum while in close contact thereto. Further, both materials are transferred between the heating drum and the endless pressing belt while being held therebetween, and the image is transferred to the image receiving material at the same time as the photosensitive material is heat developed, so that a predetermined image is formed (stored) on the image receiving material.
However, in the case where the photosensitive material is soaked in the tank in which the water acting as the image forming solvent is stored, once the water cames into contact with the photosensitive material, it becomes constantly stored in the tank. As a result of this, bacteria using traces of organic material released from the photosensitive material as a nutrition source grow in the tank so that the water is made dirty. There is thus a risk that the image forming apparatus itself deteriorates and the image quality drops.
Accordingly, a method in which the water supply side, such as the tank, is not in contact with the photosensitive material, and a nozzle plate having nozzles is vibrated so that small water drops are injected from an injector to the photosensitive material and is applied thereto has been thought of.
However, when only the photosensitive material is transferred by a transfer roller, and water drops are simply injected, it is not possible to maintain an even clearance between the injector and the photosensitive material when injecting water drops. Accordingly, the photosensitive material gets too close or too far from the injector, and portions in which the water is not sufficiently supplied arise on the photosensitive material. It is hard to apply the water to the photosensitive material uniformly.
Further, after the water is applied to the photosensitive material and before it permeates into the photosensitive material, there is a risk that the image quality of the photosensitive material is lost when the transfer roller or the like comes into contact with the application surface of the photosensitive material. Accordingly, there is a necessity for transfer with no contact occurring with the photosensitive material after water application or a necessity to heat the photosensitive material so as to accelerate water permeation.
Further, a transfer roller is generally disposed downstream of the photosensitive material in the transfer direction with respect to the injector and the photosensitive material is further transferred by the transfer roller. However, when the photosensitive material enters into the transfer roller, the photosensitive material is given a shock due to a difference in transfer speed and the like, so that this also makes it hard to uniformly apply the water on the photosensitive material.
On the other hand, when the injector is filled with the water, bubbles tend to adhere to the inner wall of the injector, and bubbles entering from the nozzles along with injected water drops adhere to the inner wall of the injector and remain there. Accordingly, there is a risk of pressure loss through bubbles and deterioration of atomization is generated during the atomizing operation of the injector, causing blocking of the nozzles.
Because of this, as mentioned above, portions free of water appear on the photosensitive material, so that uniform coating of the photosensitive material is difficult.
Further, in the case where the structure that the nozzle plate having the nozzle hole is disposed between a pair of lever mechanisms in such a manner as to stride thereover and a water drop is injected by displacing the nozzle plate by means of an actuator, a space for freely swinging the lever mechanism is required in the injector. As a result of this, bumps and pits exist on the inner wall surface of the injector and the bubbles adhere well to the inner wall surface, so that the deterioration in atomization is more easily generated during the atomizing operation of the injector.